在MongoDB Java驱动程序中设置聚合管道执行超时的行为是什么?

Question

我需要设置聚合管道执行的超时。我正在使用MongoDB Java驱动程序3.2。我知道我必须使用的代码如下：

collection.aggregate(pipeline).maxTime(10, TimeUnit.SECONDS);

问题是，一旦达到超时，我就无法在任何地方找到程序的行为。它是否抛出了异常？它是否以静默方式终止，返回null结果？

MongoDB官方文档什么也没说(参见cursor.maxTimeMS(((。此外，Java API 不引用任何特定行为(参见 maxTime(。

怎么可能？！

Answer 1

好的，我知道了。如果聚合管道的执行超过通过该方法表示的时间maxTime则会引发com.mongodb.MongoExecutionTimeoutException。

异常的堆栈跟踪如下：

com.mongodb.MongoExecutionTimeoutException: operation exceeded time limit
    at com.mongodb.connection.ProtocolHelper.createSpecialException(ProtocolHelper.java:157)
    at com.mongodb.connection.ProtocolHelper.getCommandFailureException(ProtocolHelper.java:111)
    at com.mongodb.connection.CommandProtocol.execute(CommandProtocol.java:114)
    at com.mongodb.connection.DefaultServer$DefaultServerProtocolExecutor.execute(DefaultServer.java:159)
    at com.mongodb.connection.DefaultServerConnection.executeProtocol(DefaultServerConnection.java:286)
    at com.mongodb.connection.DefaultServerConnection.command(DefaultServerConnection.java:173)
    at com.mongodb.operation.CommandOperationHelper.executeWrappedCommandProtocol(CommandOperationHelper.java:215)
    at com.mongodb.operation.CommandOperationHelper.executeWrappedCommandProtocol(CommandOperationHelper.java:206)
    at com.mongodb.operation.CommandOperationHelper.executeWrappedCommandProtocol(CommandOperationHelper.java:112)
    at com.mongodb.operation.AggregateOperation$1.call(AggregateOperation.java:227)
    at com.mongodb.operation.AggregateOperation$1.call(AggregateOperation.java:223)
    at com.mongodb.operation.OperationHelper.withConnectionSource(OperationHelper.java:239)
    at com.mongodb.operation.OperationHelper.withConnection(OperationHelper.java:212)
    at com.mongodb.operation.AggregateOperation.execute(AggregateOperation.java:223)
    at com.mongodb.operation.AggregateOperation.execute(AggregateOperation.java:65)
    at com.mongodb.Mongo.execute(Mongo.java:772)
    at com.mongodb.Mongo$2.execute(Mongo.java:759)

希望对您有所帮助。